A long-term demasculinization of X-linked intergenic noncoding RNAs in Drosophila melanogaster.

Recent studies have revealed key roles of noncoding RNAs in sex-related pathways, but little is known about the evolutionary forces acting on these noncoding RNAs. Profiling the transcriptome of Drosophila melanogaster with whole-genome tiling arrays found that 15% of male-biased transcribed fragments are intergenic noncoding RNAs (incRNAs), suggesting a potentially important role for incRNAs in sex-related biological processes. Statistical analysis revealed a paucity of male-biased incRNAs and coding genes on the X chromosome, suggesting that similar evolutionary forces could be affecting the genomic organization of both coding and noncoding genes. Expression profiling across germline and somatic tissues further suggested that both male meiotic sex chromosome inactivation (MSCI) and sexual antagonism could contribute to the chromosomal distribution of male-biased incRNAs. Comparative sequence analysis showed that the evolutionary age of male-biased incRNAs is a significant predictor of their chromosomal locations. In addition to identifying abundant sex-biased incRNAs in the fly genome, our work unveils a global picture of the complex interplay between noncoding RNAs and sexual chromosome evolution.

近期研究揭示了非编码RNA在性别相关通路中的关键作用，但对于作用于这些非编码RNA的进化力量知之甚少。利用全基因组芯片对黑腹果蝇的转录组进行分析发现，15%的雄性偏向转录片段是基因间非编码RNA（incRNAs），这表明incRNAs在性别相关生物过程中可能具有重要作用。统计分析显示，X染色体上雄性偏向的incRNAs和编码基因较少，这表明相似的进化力量可能影响编码基因和非编码基因的基因组结构。生殖系和体细胞组织的表达谱分析进一步表明，雄性减数分裂性染色体失活（MSCI）和性别拮抗都可能影响雄性偏向的incRNAs的染色体分布。比较序列分析表明，雄性偏向的incRNAs的进化年龄是其染色体位置的一个重要预测因子。除了在果蝇基因组中鉴定出大量性别偏向的incRNAs外，我们的工作还揭示了非编码RNA与性染色体进化之间复杂相互作用的全局图景。